Flashcards: Astronomical hypotheses

In planetary astronomy and astrobiology, the Rare Earth Hypothesis argues that the origin of life and the evolution of biological complexity such as sexually reproducing, multicellular organisms on Earth (and, subsequently, human intelligence) required an improbable combination of astrophysical and geological events and circumstances.

The heat death of the universe is a possible ultimate fate of the universe in which the universe has diminished to a state of no thermodynamic free energy and therefore can no longer sustain processes that increase entropy (including computation and life).

A wormhole or "Einstein-Rosen Bridge" is a hypothetical topological feature that would fundamentally be a shortcut connecting two separate points in spacetime.

In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.

The anthropic principle (from Greek anthropos, meaning "human") is the philosophical consideration that observations of the Universe must be compatible with the conscious and sapient life that observes it.

In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) is the value of the energy density of the vacuum of space.

The Gaia hypothesis, also known as Gaia theory or Gaia principle, proposes that organisms interact with their inorganic surroundings on Earth to form a synergistic self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.

The multiverse (or meta-universe) is the hypothetical set of finite and infinite possible universes, including the universe in which we live.

The inflaton is a hypothetical scalar fieldthat is supposed to be responsible for cosmic inflationin the very early universe.

Tired light is a class of hypothetical redshift mechanisms that was proposed as an alternative explanation for the redshift-distance relationship.

Mysterium Cosmographicum (lit. The Cosmographic Mystery, alternately translated Cosmic Mystery, The Secret of the World or some variation) is an astronomy book by the German astronomer Johannes Kepler, published at Tübingen in 1596 and in a second edition in 1621.

Brane cosmology refers to several theories in particle physics and cosmology related to string theory, superstring theory and M-theory.